ABSTRACTBackground.The factors influencing the acquisition and prevalence of Helicobacter pylori infection remain incompletely understood. In Russia, the demographic and socioeconomic factors are relatively similar, allowing investigation of risk factors that might not be identifiable in a more diverse population. Materials and Methods.Sero‐prevalence of H. pylori infection was studied in 520 asymptomatic individuals between the ages of 1 and 75 years, residing in St. Petersburg, Russia. Forty‐four children lived in orphanages or communal apartments. Demographic information and socioeconomic factors were evaluated, including educational level, income, and living conditions. Helicobacter pylori status was evaluated by using an enzyme‐linked immunosorbent assay for anti‐H. pylori IgG. Results.The prevalence of H. pylori infection was 44% in children and 88% in adults (P < .001). In adults, H. pylori prevalence was independent of socioeconomic factors. The crude and the age‐adjusted odds ratios (ORs) in children showed an inverse correlation between the mother's educational level and H. pylori seropositivity [e.g., OR, 1.8; (95% confidence interval (CI) = 1–3.2] for children whose mothers completed only 8 to 10 years of school compared to children whose mothers completed university. Overcrowding in childhood also was associated with increased H. pylori prevalence. Children from orphanages and communal apartments had the highest crowding index and also were at the greatest risk for H. pylori acquisition (age‐adjusted OR, 2.1; 95% CI = 1.2–2.5). Conclusions.The prevalence of H. pylori infection in Russia correlated with socioeconomic factors, suggesting there are differences sufficient to affect H. pylori transmission. The prevalence of H. pylori infection during childhood forms the basis for the variances in prevalence among populations.